Quadratic equation - finding $x$ given $y$ value

Question

I've been having trouble with this quadratic equation where $6639.55 = -0.06493x^2 + 22.35175x + 5065.25$. My question is, how do I find out $x$?

Thank you in advance for any advice!

Answer 1

The formula for the solution of $$ax^2+bx+c=0$$ is given by $$x_{1,2}=\frac{-b}{2a}\pm\frac{\sqrt{b^2-4ac}}{2a}$$ After simplifications you have to solve $$-0.06493x^2+22.35175x-1613.3=0$$ $$a=-0.06493$$ $$b=22.35175$$ $$c=-1613.3$$